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Old 06-30-2010, 06:37 PM   #147
speedster's Avatar
Drives: SST Camaro 2010
Join Date: Oct 2008
Location: East Coast of Florida
Posts: 5,932
Next on the list is the transmission. We tried and tried to find ways to utilize the 6L80E but at this point this is too much TQ and HP for presently available configurations. In addition - the 6L80E actually has too many gears for the SST. (It would have to be set up to start in 2nd at a track - as a general rule, the higher the output the more you want the engine to do the work and the less you rely on the multiplication of the transmission and rear gear ratio.

So after lots of digging around we settled on a Bowler 4L85E transmission. We spoke with many shops and top builders kept saying Bowler, so that is where we ended up. This transmission is the closest thing to bullet proof (outside of a non-street friendly Powerglide or Lenco) that we could find.

I will not bore you with the gory details but every part but the case is HP specific and has been replaced.

We stayed with a 2.48 first gear ratio. The transmission is 100% programmable and computer controlled. On the fly we can change transmission programs between street/strip/road race/long cruise. These programs can optimize it for power/economy or cool running.

This transmission has an extra deep pan to clear the transbrake and allow for additional fluid capacity. A neat feature alluded to earlier is that the transbrake is controlled by the right TapShift button (along with a hidden arming switch) and the left TapShift button controls the LineLoc. Stealthy.

The converter is a HD billet one that has the stall optimized for the torque curve of this engine and still retains lock-up capability.

Another reason for going to this level is that old adage - you get what you pay for. This 4L85E has already been broken in and fully dyno tested under EXTREME loads at their shop. Actually Mark (Bowler) knew the capability of the motor and after running it on the dyno, took it all back apart to check for any wear marks. He found one spot and machined that part to perfectly match its mate with a close tolerance and then put it all back together and repeated the process until it was perfect. That is just way cool...

So here are the transmission pics.
First Pic - The transmission is here !
Second Pic - Bowler 4L85E Extreme
Third Pic - Deep pan to clear the transbrake, add more fluid and strengthen the lower tranmission case.
Fourth Pic - This is the Input Shaft made from 300M. All shafts in this unit are 300M.
Fifth Pic - CNC Billet Converter - you can even see the marks in the metal where they mounted it to test it. This converter is also designed for a 6 bolt connection to the flexplate.
Sixth Pic - Note the massive welds and the thickness of the output flange. Heavy Duty stuff they built.
Attached Images

Last edited by speedster; 08-28-2010 at 07:07 AM.
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